We have continued with our solution small-angle x-ray studies of the bovine 70 kDa heat shock cognate protein, primarily utilizing a 60 kDa fragment (for which the C-terminal ~100 amino acids have been removed) which is less prone to self-aggregation than the full-length protein. Our current focus is to delineate which functional groups are required for the ATP-induced conformational change by measuring the DRg of proteins with mutations in the nucleotide binding site. We are completing measurements on seven different mutants at this time. .